Piperazine compounds



Patented Nov. 13, 1951 1:11,11'151)l PATENT .2,575,123 rnuggazny coMPoUNDs cash B. continuano, rrhomiagfn: Wicker, Gaines,-

ville; Fla.,assignors to Parke, Davis & Company;

1 This invention relates to heterocyclio nitro- -gen"co1np'ounds and to methods for' obtaining the same. More particularly, the invention relates to N-'phenyl-N.-(2-hydroXy-3-alkoxypro- 'pyDpiperazin'e compoundshaving the formula,

lig R FEF- with a 1.2.-.ep0xy-zollioxypropaue Qi .formula O @Qca-Safor@ A.Where E, R1, Ra and r'nfhaveL the saine sigerably carried out in the Vpresence 6i a small amount of water which 'appears .to function as `a catalyst. The temperatureiis 'not particularly criticaland can be variedfrcm rccmtemprature (about C.) to about 150 C."If`des`irecl, a solvent",y lsuch asl methanol, ethanol, isopropanol, loe/nze'ne, chloroorm"'and the like can be used but it is not necessary.

A variation of the above-described process involves reacting a 1,2-epoxy-3-halopropane with the N-phenylpiperazine compound to produce an N-phenyl-N-(2-hydroXy-3-halopropyl) piperazine compound of formula,

where X is a halogen atom and R1, R2 and Ra have the same significance as given above. The N- v (iClaims. (Cl.

ober 11', 11,9750,

2 phenyl N -(Z-hydrpxyl-Ef-halopropyl) piperaznine cfcin'pcund is then conve tedt the corresponding N-pncyi-N-(z-xhydrcy- -aikoiyprcpyn pipjpacompound'by reaction With an alkaliinetal methoiide or'etloizide. `Tlie""latter Vreactionis carried out by Warming or allowing the reactants to stand Ytogether in lan anhydrousprganic'isolvent'suchas methanolor ethanoll" The products NNof "th'dnverition can also be produced by the reaction of 'N-phnylpiperazine compoun'dl of formula,

with a 1-halo-2-hydroXx-S-alloxypropari@ 0f formula,

Where X is `a halogen atom and R, R1y 11.2 and R3 have' the" saine Sigriziflcanc'as givenl-above. The reaction is' `'preferably' carried out in an inert organic solvent suoli` as'nethanol, ethanol, isopropanol, benzene, Xylene, chloroform, carbon tetrachloride and the like. From thestandpoint of economy, itis also preferable to carry out the vreaction in the presence of an alkaline catalystsuwchV as an l'alkali nietall or' alkaline earth metal, carbonate, bicarbonate or hydroxideviv -If no catalyst is employed, t'wo equivalents "of the Nrphenylpiperazine' Vcompound vare""required for la oxypropane because" one equivalent' o 'f the Nfphrlylpiperazimne compound"reacts with the action to formthe hydro'gen'halide "saltof the N-phenylpiperazine. compound- Thc compounds .af 11.1,@ normal salts with both inorganic and organic acids. Some examples of suchsaylts are the hydrochloride, hydrobromide, sulfate;a"c'etate, citrate and thef like.V yThe N- phenyl-N-(Z-hydroXy-S-alkoxypropyDpiperazine compounds p'sess ahigh degree of sympatholytic activity' and a signicant degree of antihistamineactivity. They may be used for therapeutic purposes either in the free base or acid addition form. They can be administered by either the oral or parenteral routes.

The invention is illustrated by the following examples.

(a) 17.6 g. of 1,2-epoxy-S-methoxypropane is added dropwise to a mixture composed of 32.4 g. of N-phenylpiperazine and 1 cc. of water at 75" C. During the addition, which requires about ten minutes, the temperature of the reaction mixture rises to approximately 125 C. The temperature is maintained at 12B-30 C. for one hour and the mixture allowed to cool. The crystalline mass is recrystallized from boiling heptane using activated carbon to remove any colored impurities. The white crystalline N- phenyl-N' (Z-hydroxy-S -methoxypropyD piperazine so obtained melts at G25-63.5 C. (corr.)

3 g. of N-phenyl-N'-(Z-hydroXy-S-methoxypropyDpiperazine is dissolved in dry ether and the calculated quantity of hydrogen chloride dissolved in dry isopropanol is added. The White precipitate is collected and puriiied by recrystallization from isopropanol. The hydrochloride salt of N-phenyl-N'-(2-hydroxy-3-methoxypropyDpiperazine so obtained melts at i90-205 C., with decomposition.

(b) 21.7 g. of 1-chloro-2-hydroxy-3-methoxypropane is added dropwise during a period of about twenty minutes to a mixture of 32.4 g. of N-phenylpiperazine and 21.2 g. of anhydrous sodium carbonate which has been heated ten minutes on the steam bath. The resulting mixture is then heated three hours on the steam bath, poured into boiling heptane, and allowed to crystallize. The resulting crystalline mass is recrystallized from boiling heptane using activated carbon to remove any colored impurities. The product so obtained is identical in all respects to that obtained by the procedure described in (a) above.

Example 2.-N-phenyl-N'-(Z-hydroxy-S- ethomypropyl) piperazine CH2-CH2 CH2-CH: H

20.4 g. of 1,2-epoxy-S-ethoxypropane is added to 32.4 g. of N-phenylpiperazine at about 150 C. The temperature climbs to 210 C. during addition, but the reaction mixture is allowed to cool to 175 C. and is maintained at that temperature for six hours. The mixture is then allowed to crystallize and is recrystallized from boiling heptane using activated charcoal to remove colored impurities. The white crystalline N-phenyl-N'- (2-hydroxy-3 -ethoxypropyD piperazine so obtained melts at G15-62.7 C. (corn).

82 g. of 1,2-epoxy-3-methoxypropane is added dropwise to a mixture composed of 9.5 g. of 1- phenyl-3,5-dimethylpiperazine and 0.5 ce. of

water. During the addition the temperature is maintained at -100" C. The reaction mixture is heated for one hour after the addition has been completed and then cooled. The crystalline product is taken up in and recrystallized from boiling heptane to obtain the desired 1phenyl 3,5-dimethyl-4-(2-hydroxy 3 methoxypropyl) piperazine as a white crystalline solid.

11.8 g. of 1,2-epoxy-3-methoxypropane is added dropwise to a mixture composed of 12.6 g. of 1-phenyl-2,S-dimethylpiperazine and 0.5 cc. of water at about 80 C. During the addition the temperature of the reaction mixture rises to approximately C. The temperature is maintained at 120 C. for one hour and then the mixture allowed to cool. The crystalline mass'is recrystallized from boiling heptane to obtain the desired 1phenyl-2,5dimethyl4(2- hydroxy-S-methoxypropyl)piperazine ln pure form.

What We claim is: 1. A compound of the class consisting of a free base and its acid addition salts. said free base having the Iformula.,

CH2-C ji. Where R is a member of the class consisting of CH3 and C21-I5 and R1, R2 and Ra are members of the class consisting of hydrogen and methyl groups.

2. Nphenyl-N(2 hydroxy 3 methoxypropyl) piperazine.

3. The hydrochloride salt of N-phenyl-N'(2 hydroxy-S-methoxypropyl) piperazine.

4. Nphenyl-N(2hydroxy3 ethoxypropyl) piperazine. 5. 1phenyl3,5dimethyl 4 (2 hydroxy 3- methoxypropyl) piperazine.

6. 1phenyl2,5dimethy l 4 (2 hydroxy 3- methoxypropyl) piperazine.

CASH B. POLLARD. THOMAS H. WICKER.

No references cited. 

1. A COMPOUND OF THE CLASS CONSISTING OF A FREE BASE AND ITS ACID ADDITION SALTS, SAID FREE BASE HAVING THE FORMULA, 